ML14183A095
| ML14183A095 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 03/31/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML14183A094 | List: |
| References | |
| NUDOCS 8704150029 | |
| Download: ML14183A095 (3) | |
Text
~P oREG&
UNITED STATES 0
NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.113 TO FACILITY OPERATING LICENSE NO. DPR-23 CAROLINA POWER AND LIGHT COMPANY H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261 I. INTRODUCTION By letter dated December 18, 1986, Carolina Power & Light Company (the licensee) submitted a request for revision to the Technical Specifications for the H. B. Robinson Steam Electric Plant U1nit 2 (HBR-2). The proposed license amendment will incorporate new reactor vessel heatup and cooldown pressure temperature limit curves which will replace the existing Figures 3.1-1 and 3.1-2, respectively. Two sets of curves applicable for up to 12.5 and 15 effective full power years (EFPY) were proposed. The bases for the proposed heatup and cooldown limits are the test results from the HBR-2 surveillance program (Reference 1) submitted for staff review in a letter from the licensee to the NRC dated August 19, 1983.
II. EVALUATION Pressure-temperature limits must be calculated in accordance with the require ments of Appendix G, 10 CFR 50, which became effective on July 26, 1983.
Pressure-temperature limits that are calculated in accordance with the require ments of Appendix G, 10 CFR 50, are dependent upon the initial reference temperature (RT g T) for the limitino materials in the beltline and closure flange regions 5the reactor vessel and the increase in RT YlT resultina from neutron irradiation damage to the limiting beltline materiaT The licensee indicated that the initial RT for the limitina materials in the closure flange and beltline regions oXthe HBR-2 vessel were estimated using the method recommended by the staff in Branch Technical Position MTEB 5-2, "Fracture Toughness Requirements," which is documented in the Standard Review Plan, Section 5.3.2, "Pressure-Temperature Limits."
The limiting beltline material is the upper circumferential weld fabricated using RACO 3 wire (heat no. W52141 and Linde 1092 flux with nickel added. The licensee indicates that Branch Technical Position MTEB 5-2 results in an initial RT of 0 F for the limitina weld metal.
The licensee indicates that the limiti NTclosure flange region materia is the vessel flange forging, in which the initial RTNDT is estimated as 40 F (Reference 21.
6704150029 870331 POR ADOCK 05000261 P
-2 The increase in RT resulting from neutron irradiation damage depends upon the predicted amou H'of neutron fluence and the rate of embrittlement of the limiting reactor vessel beltline material. The licensee indicated that te 2
neutron fluence at the inside surface of the limiting weld was 13.5 x 10 n/cm at 7.48 EFPYI nd thgt the subsequent rate of increase in fluence would be 1.05 x 10 n/cm per EFPY (Reference 2).
For the limiting weld at the inside surface, this rate of Increape in neutron Buence2 results in predicted neutron fluences of 1.9 x 10 n/cm and 2.1 x 10 n/cm at 12.5 and 15 EFPY, respectively.
The increase in RT resulting from neutron irradiation damage was estimated by the licensee ac 9rding to Regulatory Guide 1.99 Rev. 1, "Effects of Residual Elements on Predicted Radiation Damage to Reactor Vessel Materials."
Reference 2 contains a comparison of the observed increase in PT T of the surveillance weld metal and that predicted according to Regulatop Guide 1.99 Rev. 1 for HBR-2. The surveillance material test results indicate that the increase in RT,of the surveillance material is less than that predicted by Regulatory Gui T1.99 Rev. 1. The licensee indicates that the surveillance weld metal is the limitina weld material (Reference 3). Hence, the Regulatory Guide should provide a conservative estimate as to the amount of increase in RT resultina from neutron irradiation for the HBR-2 limitino reactor vessel be Tine material.
The staff used the unirradiated RT NT for beltline and closure flange materials, which were previously discussed, t i neutron fluence estimates of the licensee, the Regulatory Guide 1.99 Rev. 1 method of estimating neutron irradiation damage, and Standard Review Plan 5.3.2 method of calculating pressure-temperature limits to evaluate the licensee's proposed pressure-temperature limits. Our evaluation indicates that the proposed pressure-temperature limits in Figures 3.1-1.a and 3.1-2.a meet the safety margins of Appendix G, 10 CFR 50, for a period of time corresponding to 12.5 EFPY. Also, it indicates that the proposed pressure temperature limits in Figures 3.1-1.b and 3.1-2.b meet the same safety margins for a period of time corresponding to 15 EFPY.
III.
SUMMARY
Based on the above discussion, the staff finds the proposed licensee amendment acceptable.
IV. ENVIRONMENTAL CONSIDERATION This amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
V. -CONCL'ISION We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
REFERENCES (1) Westinghouse Report WCAP-10304, "Analysis of Capsule T From the H. 8.
Robinson Unit 2 Reactor Vessel Radiation Surveillance Program,"
S. E. Yanichko, S. L. Anderson, R. P. Shogan, and R. G. Lott, March 1983.
(2) Letter from G. Requa (NRC) to E. E. Utley (CP&L) dated September 4, 1984.
(3) Letter from S. R. Zimmerman (CP&L) to NRC Document Control Desk dated January 16, 1987.
Dated:
March 31, 1987 Principal Contributor:
S. Lee